The present invention relates to a high security seal of the padlock type and, more particularly, to a seal having a wire shackle that is first threaded through a structure to be secured and then locked in a seal body such that the seal must be broken to be opened. The present invention also relates to a method of making such seals.
Security seals of the padlock type are generally well known, and they have found wide spread use for sealing structures such as currency bags, closures, electric meters, and the like. Examples of such seals may be found in the following U.S. Patents: U.S. Pat. Nos. 3,485,461; 3,373,033; 3,980,332; 4,353,583; 4,278,281; 4,687,240; 4,832,387 and 4,775,175.
All of these seals have, generally, a plastic body with a pair of spaced cavities in which a U-shaped shackle is permanently locked. Locking the shackle is typically accomplished by a pair of reversely bent, resilient legs that register with a bump or depression located in the spaced cavities.
The present invention is an improvement of the security seal disclosed in these latter two patents. In the '175 Patent, the plastic body of the seal disclosed therein includes a central cavity in which an ampule containing a liquid, which may be brightly colored, is inserted. When the reversely-bent, sharp ends of the shackle, located within the plastic body of the seal, are attempted to be removed from the body, penetrate into the central chamber and shatter the impule, cause the liquid therein to seep from the central chamber through the ruptured sidewalls of that chamber. Also, an external aperture is provided over the central chamber to permit the liquid to seep into the ambient atmosphere region of the plastic body. When the liquid seeps through the ruptured sidewalls, it may or may not reach the shackle openings and therefore be visible external the plastic body. The plastic body is opaque and, therefore, the liquid is required to seep to an external region in order to be visible. Observation of the liquid external the body indicates tampering with the seal.
In the '387 Patent, a padlock-type security seal having a shackle and a plastic body and an insert are disclosed. The insert and plastic body are opaque and, in contrast to the '175 Patent, no liquid is used in this embodiment, as disclosed in the '387 Patent. The problem with this structure is that, when the shackle is attempted to be removed from the locked engaged position within the padlock, the sharp, reversely-bent ends of the shackle within the padlock are forced against the insert and then are bent outwardly and penetrate through the padlock body case. The present invention is a recognition of the problems associated with the above two described patents and it is an improvement thereover.